1. Field of the Invention
The present invention relates to a bar code scanner (reader) for reading a bar code by applying light emitted from a light source such as a laser diode or the like to a bar code portion and receiving its reflected light by means of a light receiving element.
2. Description of the Related Art
A bar code scanner is an apparatus which applies light such as a laser beam emitted from a light source toward a bar code portion where a bar code is printed on a case or a package of a product and reads the bar code from an electronic signal obtained by receiving its reflected light. By virtue of an advantage of being able to read a bar code even if the bar code scanner is away from the bar code portion, it is widely used in a distribution field, sales and management departments, and the like these days.
Such a bar code scanner is disclosed in, for example, Japanese Utility Model Laid-open Publication No. 62-62375.
This bar code scanner houses and holds a sensor body 52 and a printed board 50 with electric processing circuits 53 being mounted thereon which are electrically connected in a split case 51 which is split into an upper case 54 and a lower case 55 as shown in FIG. 8.
In the bar code scanner, a coupling cap 56 fits over extending cylindrical portions 54a and 55a which are respectively formed at the right end portions in FIG. 8 of the upper case 54 and the lower case 55 of the split case 51 with components to be housed such as the sensor body 52, the printed board 50, and the like being set at predetermined positions in the split case 51.
Further, an intermediate cap 57 fits over extending cylindrical portions 54b, 55b which are respectively formed at the left end portions of the upper case 54 and the lower case 55.
The sensor body 52 housed in the split case 51 houses a light emitting element such as an LED or the like and a light receiving element such as a transistor or the like at predetermined positions in an outer case 58 which can be vertically split.
Such a fixed structure of a circuit board which is provided in the bar code scanner is disclosed in, for example, Japanese Utility Model Publication No. 4-49726. 
In this bar code scanner, a rear end portion of a main body cover 61 is opened and a plurality of recessed portions 68 are formed in the inner face thereof near the opening, and a rear cover 62 provided with a plurality of spring-loaded engaging hooks 70 extending toward the inside of the main body cover 61 is fixed to the main body cover 61 by engaging the engaging hooks 70 to the plurality of recessed portions 68 respectively as shown in FIG. 9.
A circuit board 63 on which an optical scanner unit 69 is mounted at the front end portion and to which a cable 64 is connected at the rear end portion is attached to the rear cover 62. Accordingly, as for the bar code scanner, the circuit board 63 is inserted to a predetermined position shown in FIG. 9 in the main body cover 61, and the engaging hooks 70 of the rear cover 62 are engaged to the plurality of the recessed portions 68 of the main body cover 61, thereby completing attachment of the circuit board 63 to the inside of the main body cover 61.
Some bar code scanner scans the top of a bar code face by directing a beam of light emitted from a light source such as a laser diode to right and left by a mirror (a deflection member) attached to a rotating shaft of a motor, receives its reflected light by a light receiving element, and decodes numerals, symbols, and the like on the bar code by a detection signal from the light receiving element.
However, as is clear from FIG. 8, in the aforesaid bar code scanner disclosed in Japanese Utility Model Laid-open Publication No. 62-62375, the electric processing circuits for controlling various kinds of operations of the bar code scanner are closely provided on one circuit board, provided in the pen-type elongated split case such that the whole circuit board extends along the longitudinal direction of the split case, thereby bringing about a problem that the whole length of the bar code scanner becomes longer than required.
In the case of the latter bar code scanner disclosed in Japanese Utility Model Publication No. 4-49726, the rear cover is fixed to the main body cover by respectively engaging the spring-loaded engaging hooks which are formed at the rear cover in correspondence with the plurality of recessed portions formed in the inner face of the main body cover near the rear end portion, to the recessed portions. The engagement fixes the circuit board provided integrally with the rear cover at a predetermined position, resulting in occurrence of inconveniences when the bar code scanner is dropped by accident.
In other words, in the case of the handy-type bar code scanner of this pen type, it is normally used by being held by a hand, and thus it is often dropped on the floor or the like by accident.
At that time, for example, in the case of the bar code scanner of the type which deflects a beam of light emitted from a light source by a mirror which is rotated by a motor to scan the top of a bar code face, a component especially with a certain weight as a motor is susceptible to displacement due to the impact upon a drop.
The present invention is made in view of the aforesaid problems, and its object is to downsize a bar code scanner for reading a bar code using a beam of light emitted from a light source without making it longer than required. Another object is to assure location accuracy of components embedded in the bar code scanner even when it is dropped by accident.
In order to attain the above objects, in this invention, a bar code scanner comprising: a laser diode whose operation is controlled by a laser diode control section; a deflection member for reflecting a laser beam emitted from the laser diode and passing through a collimate lens into a collimated beam; a scanning deflection member for deflecting the laser beam from the deflection member to scan a bar code portion; a scanning deflection member control section for controlling drive of the scanning deflection member; a light receiving element for receiving reflected light that the laser beam strikes the bar code portion and is reflected; and an electric signal processing section for processing an electronic signal outputted from the light receiving element, is structured as follows.
A laser diode control board provided with the laser diode control section, a scanning deflection member control board provided with the scanning deflection member control section, and an electric signal processing board provided with the electric signal processing section are formed of individual boards, and the laser diode control board, the scanning deflection member control board, the electric signal processing board, the laser diode, the collimate lens, the deflection member, the scanning deflection member, and the light receiving element are individually attached to one holding member to form the bar code scanner.
Further, it is desirable to structure the bar code scanner as follows.
In the above bar code scanner, the deflection member is disposed at the front in an irradiation direction of the laser beam emitted from the laser diode to the collimate lens, and the laser diode control board is disposed on the side opposite to the collimate lens with respect to the laser diode to be orthogonal to a top face of the holding member such that a board face thereof closely faces the laser diode.
The scanning deflection member is disposed to be closely situated next to the collimate lens and to be at the same height as that of the collimate lens, and the electric signal processing board is disposed below the collimate lens along the irradiation direction of the laser beam in a position orthogonal to the top and bottom faces of the holding member.
Further, the light receiving element is disposed below the scanning deflection member, and the scanning deflection member control board is disposed at the rear in the irradiation direction of the laser beam with respect to the scanning deflection member.
Furthermore, it is preferable that the laser diode control board, the scanning deflection member control board, and the electric signal processing board are individually fixed to the holding member by screws.
Moreover, it is effective that a cover for covering the holding member to which the boards are individually screwed is provided, and the cover is fixed to the holding member by a screw.
The above and other objects, features and advantages of the invention will be apparent from the following detailed description which is to be read in conjunction with the accompanying drawings.